2 motors, 2 batteries and 2switches

[US1Fountain]

Purchased my boat last fall and have noticed the battery switches don't behave as I'd think. I can not disconnect the house panel from the battery. I can disconnect each motor at its switch. Looking at how they are wired, the COMMON terminal goes to the starter. The BAT 1 and BAT 2 are connected to the batteries, and also with jumpers between the 2 switches so they can be connected. These are 1, 2 and Both switches. The house panel is connected at 1 of the switches to the BAT1 terminal. So no matter what position the switch is in, the house panel is always powered. It can not be disconnected by the switch. The only purpose of the switches are to disconnect the motors, or switch to a charged battery if the other battery is to go dead.
Im not so sure I like this configuration. My thinking is to connect each of the COMMON terminals to the battery pos cable of its switch. This will allow me to kill all power if the need arises.
This is how the boat is wired from the factory, and is illustrated in owners manual. My previous boat, same make and model was wired same way. Im trying to understand the purpose/benefit of being wired this way.
Looking for opinions of pros/cons of either current or proposed method.

Thanks

[billknny]

I agree with your inclination.

Battery switches are an important safety device, and should be able to turn off power to everything on the boat in the even of an electrical fire, for example. Or maybe a winch or windlass where a stuck relay will not allow it to be shut off.

[john61ct]

Battery on/off switches should isolate that bank from Everything, right after the bank's fuse. Ensure that engines are off, or at least alt field current is off, before opening.

1-2-B switches should be wired to direct **loads** between banks, not charge sources.

[smac999]

add a 3rd house battery and 3rd switch.

leave engine switches as is. they are wired perfectly for 2 engines from 2 engine switches and 2 engine batteries.

or add 3rd 1/2/all swtich for house. so you can power the house off either battery as well. but you are draining from an engine battery. (like you are now)

[US1Fountain]

Originally Posted by smac999

add a 3rd house battery and 3rd switch.

leave engine switches as is. they are wired perfectly for 2 engines from 2 engine switches and 2 engine batteries.

or add 3rd 1/2/all swtich for house. so you can power the house off either battery as well. but you are draining from an engine battery. (like you are now)

You are correct, the house is drawing off the engine battery. I am going to go with your last comment and use 1 engine battery as the house also. My needs/use does not require a dedicated house bank and a shared start battery will be just fine. I just need to get the switches and wiring organized so that I can disconnect everything and control the flow path. Unlike it is now which has me scratching my head wondering what the manufactures line of thought was.

[ranger58sb]

Originally Posted by US1Fountain

So no matter what position the switch is in, the house panel is always powered. It can not be disconnected by the switch. The only purpose of the switches are to disconnect the motors, or switch to a charged battery if the other battery is to go dead.

What runs your bilge pumps? House circuitry? If so, maybe that's why the house is always powered?

-Chris

[US1Fountain]

Bilge pump is wired direct to battery. However, the Mecathodes are powered off the starter lug, so switching off the battery switch will render the Mercathodes inoperative.